- Study Site There are 6 visits in the study. The purpose of the Visit 1 will be to determine and confirm the eligibility of patients for participation in the StELLAR Study and document baseline information about the subject and their stroke event. This will include all of the following standard of care tests and procedures: a non contrast head CT scan performed prior to rt-PA administration, vital signs, height , weight ,physical exam, finger stick or blood glucose, serum or urine pregnancy test (if women of childbearing potential). In addition, the following data will be obtained: prestroke mRS, NIHSS, presumed location of stroke and vascular territory, start and stop date and time of the IV rt-PA treatment and dose given, date and time of stroke onset, date and time of arrival to the hospital, demographic data (date of birth, gender, ethnicity),sociodemographic data (education, marital status, social support prior to stroke),medical and surgical history (specific cardiovascular, neurological, endocrine, and other standard questions asked), method of contraception use (for women of child bearing potential), prior (three days prior to Screening) and current concomitant medication use, smoking history, adverse events from the time of obtaining informed consent. To be eligible for the study, the administration of rt-PA should follow the guidelines outlined by the National Institutes of Neurologic Disorders. Patients meeting the inclusion/exclusion criteria will be enrolled into the study after written informed consent is obtained by the patient or their legally authorized representative.